I wanted to install Maia so I followed this guide.
The problem is the step

passwd amavis

which gives me

/usr/src/maia# passwd amavis
passwd: Authentication service cannot retrieve authentication info.
passwd: password unchanged

What can I do?
Thanks for help.

sounds like a pam error... Do you need pam in your installation? Show us your /etc/nsswitch.conf...

pam?
Never heard about that.
I just followed the guide.
/etc/nsswitch.conf:

passwd: compat
group: compat
shadow: compat

hosts: files dns
networks: files

protocols: db files
services: db files
ethers: db files
rpc: db files

netgroup: nis

have you updated your system?

set
passwd: files nis
group: files nis
shadow: files nis


and try again...

I have followed the guide so I did this update:

apt-get update && upgrade

passwd: files nis
group: files nis
shadow: files nis

doesn't help.
What should I do now?
Thanks.

but there is a amavis user on your system?

passwd root works. Seems to be a problem with the user amavis. How can I fix this?
passwd:

amavis:x:108:110:AMaViS system user,,,:/var/lib/amavis:/bin/false

gshadow:

clamav:!::
amavis:!::clamav

group:

clamav:x:109:
amavis:x:110:clamav

shadow:

no entry!